Here's why:
* Exposure: The photographs were taken during the day on the moon, with the sun shining brightly. This means the exposure settings had to be adjusted to capture the details of the lunar surface, which resulted in the stars being underexposed.
* Brightness: The moon's surface reflects a lot of sunlight, making the sky brighter than it would be on Earth at night. This makes it even harder to see faint stars.
* Lens Flares: The intense sunlight could also have created lens flares in the photographs, obscuring some of the stars.
* Dust and Particles: There is always dust and particles floating around in the atmosphere, and this can also scatter light and make it difficult to see stars.
Furthermore, some of the Apollo mission photographs that are often used to support the "no stars" conspiracy theory were actually taken inside the lunar module, where there wouldn't be any stars visible anyway.
While it's true that stars are not prominently visible in all the Apollo mission photographs, this does not indicate any sort of conspiracy or hoax. It's simply a matter of the limitations of photography and the conditions on the moon.
You can find more detailed explanations and examples of photos with stars on NASA's website and in reputable sources like scientific journals and articles.